MatchScale is a web-based compatibility testing system developed by PsychTests for dating websites. It analyzes 152 attributes, including personality traits, relationship philosophies, communication styles and general values. To find partners with just the right mix of similar and complementary characteristics, MatchScale's artificial intelligence methods compare the trait patterns of the potential couples. Users are then matched with partners who have enough in common to make the relationship stable and safe, and who, at the same time, are different enough to provide variety to help them grow.